Height or distance measurement has a wide variety of possible application. However, the environment where the height measurement is to be conducted provides a lot of difficulties. In particular when applying a height measurement in the automotive technology, for example to measure a level of a vehicle frame with respect to the road or between the car chassis and the suspension beam, the environment of the height measurement, in particular the distance between the frame of vehicle and the road is very noisy, very dirty and provides high vibrations.
From DE 10 2006 017 275 A1 for example an air spring and a positioning of an air spring is known, wherein the distance between two parts of the air spring can be measured by an analogue proximity sensor. Commonly used proximity sensors are for example based on an ultrasonic measurement principle, which, however, is very sensitive in noisy and vibrating environments, as the acoustic noise and the ultrasonic measurement principle are based on the same physical principle, i.e. sound propagation.
Further, DE 10 2008 064 647 A1 describes an air spring for a vehicle having a measuring device, which measuring device may transmit data and energy via predetermined and fixed distance contactless.